Holder for magnetic sensitive element

ABSTRACT

A holder for holding a magnetic sensitive element by which the magnetic sensitive element may be secured at a desired position so as to obtain favorable output characteristics and to reduce the area which the element occupies. The holder positions the magnetic sensitive element opposite a magnetic drum, within a magnetic encoder, and comprises a movable holder for holding a magnetic sensitive element connected to a flexible signal input/output member, a fixed holder fixed to a circuit board for holding the movable holder, and a guide which is biased against the movable holder to permit movement of the movable holder in a direction perpendicular to the magnetic sensitive surface of the magnetic sensitive element to a desired set position to thereby adjust the gap between the magnetic sensitive element and the magnetic drum.

TECHNICAL FIELD

The present invention relates to a holder for holding a magneticsensitive element to secure it at a predetermined position. Morespecifically, the present invention relates to a holder for magneticsensitive elements which can be applied to a magnetic encoder.

TECHNICAL TERMS

In the specification of the present application, the term "holder" meansa part for securing a magnetic sensitive element and includes signallines for input/output terminals. The term "magnetic sensitive element"is what can be described as a magnetism sensor for detecting magneticenergy, and embraces a magneto-resistance element, a Hall element, athin-film magnetic head and the like.

BACKGROUND ART

Conventionally, a magnetic sensitive element 4, which is used with amagnetic encoder or the like, is secured to a holder 11 as shown in FIG.12, and so arranged therein as to opposingly face a magnetic drum with apredetermined gap provided therebetween. As disclosed in, for example,Japanese Utility Model Laid-Open Publication No. Sho. 62-20,313, theholder 11 for such a magnetic sensitive element 4 comprises apositioning pin 11b and an adjustment slot 11a such that a machine screw10 is inserted through the slot 11a with the pin 11b fitted into apositioning hole formed in a circuit board, thereby securing the holder11 to the circuit board. The gap between the magnetic drum and theholder 11 can be adjusted by utilizing the slot 11a. Another type ofholder is known in which, as shown in FIG. 13, an H-shaped separableholder 13, having the magnetic sensitive element 4 secured thereto, iscombined with a fixed holder 12 having a pair of right and left guidewalls 12a and a pair of right and left grooves 12b, the H-shapedseparable holder 13 being fitted vertically in between the guide walls12a and the grooves 12b. This holder is also arranged to enable theaforesaid gap to be adjusted by moving the fixed holder 12 per se viaright and left slots 12c formed in the fixed holder 12. The holderdisclosed in Japanese Patent Laid-Open Publication No. Sho. 61-165,621is, as shown in FIG. 18, separated into a movable holder 14 in which issecured a magnetic sensitive element and a fixed holder 15 for holdingthe movable holder 14. The movable holder 14 is movably accommodated inthe fixed holder 15, and to move the movable holder 14 forwardly andbackwardly via a gap adjustment screw 16 and spring 17 will effect apositional adjustment of the movable holder 14 relative to the fixed one15.

However, if the slot 11a or 12c is to be formed which allows the holder11 or 12 to be secured to the circuit board or the like so that theholder 11 or 12 can be moved for fine adjustment, it is necessary toform the holder into a shape projecting in the rightward and leftwarddirections. This results in disadvantage that it is impossible tominiaturize the holder because of the increased holder size. The holdershown in FIG. 18 also has the problem that the holder size increasessince screw-mounting holes 18 for securing the fixed holder 15 to theboard need to be formed on right and left sides. As a result, such aholder occupies a wide area on the board. Another problem is that costsincrease since the machine screw 10 is used for securing the holder tothe board and thus such working step as a tapping is needed. Thearrangement in which the movable holder 14 is moved for adjustment bymeans of the gap adjustment screw 16 has the disadvantage that anextremely complicated and large structure is needed for accommodatingthe adjustment screw 16 and the spring 17.

As shown in FIG. 14, the magneto-resistive element 4 has a resistancepattern which is generally formed by a plurality of resistors R₁, R₂, R₃and R₄. It is desirable that this resistance pattern, which facestowards a magnetic drum 8, should be disposed parallel to a tangent Textending to touch one point closest to the center of the magneticsensitive surface 4a of a magnetic recording medium 9 secured to themagnetic drum 8. With the magnetic sensitive element 4 inclined by anangle θ with respect to the magnetic recording medium 9, the resistorR₁, closest to the magnetic recording medium 9, is exposed to thestrongest magnetic field, while the resistor R₄, the most remote fromthe magnetic recording medium 9, is exposed to the weakest magneticfiled. This can also be seen from FIG. 15 which shows the effectivemagnetic filed strength of the magnetic sensitive element 4 with respectto the gap between the magnetic recording medium and the magneticsensitive element 4. However, turning to FIG. 12, the holder structureis such that adjustment of the gap is performed by means of thepositioning pin 11b and slot 11a, according to which, the magneticsensitive surface 4a is inclined by angle of θ relative to a plane Tparallel to the tangent T, with movement of the holder 11 for the gapwidening purpose, and consequently the resistance pattern is not set inparallel with the magnetic sensitive surface 4a. The holder structure asin FIG. 13, which has the slots 12c on the right and left sides, has asimilar problem in that it is difficult to move the magnetic sensitiveelement 4 in parallel. In the case of the holder structure of FIG. 18 inwhich the movable holder 14 is moved for fine adjustment and secured inposition by using the adjustment screw 16, since the movable holder 14is not fixed to the fixed holder 15, the position or the inclination ofthe movable holder 14 may be shifted due to various factors such asvibration or a change in the position or the direction in which theelastic force of the spring 17 is to be imparted. This may possibly leadto a deterioration in output characteristics.

The resistors R₁ to R₄ are generally connected together as shown in FIG.16, and, if difference occurs in magnetic field strength among thoseresistors, an A-phase output becomes larger than a B-phase output. Inaddition, difference also occurs in sensitivity among the resistors R₁to R₄, affecting resulting output waveform to show a biased ratio of thepositive part to negative part in that waveform and producing thefluctuation of an output signal due to jitters. The smaller is themagnetizing pitch of the magnetic recording medium, the more seriousbecomes such output problem. Hence, in this particular prior art, withincrease of the angle θ between the magnetic sensitive surface 4a andthe tangent T (or the parallel plane T₁) associated with the magneticrecording medium 9, several electrical characteristics involved are moresubject to enormous variations. Such is the case as shown in FIG. 17,wherein, as the angle θ is greater, a resulting waveform is shown to bedistorted by the solid line d in reference to a dashed line c indicativeof "θ≈0", which means deterioration of the output characteristicsinvolved.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a holder formagnetic sensitive elements in which a fixed holder is so miniaturizedand simplified as to provide a reduced area to be occupied by themagnetic sensitive element and attain good output characteristics.

A holder for magnetic sensitive elements according to the presentinvention comprises: a movable holder for holding a magnetic sensitiveelement to which a flexible signal input/output member is connected; afixed holder fixed to a board for holding the movable holder; and guidemeans for guiding the movable holder for movement in one direction witharrangement that a guide portion formed on the fixed holder is given anelasticity so as to elastically urge a guide portion formed on themovable holder between the fixed holder and the movable holdercharacterized in that, a direction of movement of the movable holderbeing made the same as the direction perpendicular to the magneticsensitive surface of the magnetic sensitive element.

Accordingly, in an arrangement where the holder for magnetic sensitiveelements according to the present invention is disposed in opposition tothe magnetic drum or the like, by mounting the fixed holder on the boardso that a moving axis at the center of the magnetic sensitive surface ofthe movable holder coincides with an arbitrary normal of the magneticdrum, a tangent which extends to touch one point which is the closest tothe holder for the magnetic recording medium is made parallel to themagnetic sensitive surface, and the magnetic sensitive surface movesparallel to the aforesaid tangent. Accordingly, gap adjustment can beeasily accomplished and A- and B-phase outputs can be made uniform. Itis therefore possible to improve output characteristics while reducingvariations in characteristics. The holder according to the presentinvention is separated into the movable holder including the flexiblesignal input/output member and the fixed holder. Accordingly, if thefixed holder is formed as a solderable chip, the fixed holder can beautomatically mounted on a circuit board together with another circuitelement by a chip mounter or the like, whereby connection can be easilyachieved by soldering or the like and an improvement in productivity anda great reduction in the cost of assembly can be achieved. In addition,according to the present invention, it is not necessary to make theholder partially project to the right and left sides for the purpose offorming screw-mounting holes for securing the fixed holder to the board,whereby the entire holder can be miniaturized and the area occupied bythe holder can be reduced. In addition, since parts such as adjustmentscrews or springs for moving the movable holder for fine movement arenot needed, a simple, small and inexpensive structure can be adopted.According to the invention, the fixed holder is formed from a metallicplate and thus the holder is not only of a certain rigidity of anunchangeable hard nature but also allows for being formed into a verythin structure. Further, the area of the fixed holder may suffice if itis equal to that of the movable holder, which render smaller the entiresize of the holder.

Furthermore, in the present invention, if the fixed holder 2 is formedfrom a magnetic metallic sheet, this serves as a magnetic shield.Accordingly, when the holder is used in a motor or the like, it ispossible to suppress magnetic noise generated from a driving magnet orother disturbance factors.

In another aspect of the invention, an adhesive reservoir is formed inan upper portion of the guide portion formed on the movable holder, andthus, by simply injecting an adhesive agent into the reservoir, themovable holder is fixed unmoved at a given position relative to thefixed holder.

In still another aspect, a holder, having the magnetic sensitive elementretained thereon, is applied as elastic urging force from the fixedholder soldered on the circuit board, with the magnetic sensitivesurface of the magnetic sensitive element being disposed opposite to amagnetic recording medium and a gap being provided therebetween.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 through 11 show embodiments of the present invention, wherein

FIG. 1 is a perspective view showing in assembled form one embodiment ofa holder for magnetic sensitive elements, where the holder is shown asholding a magnetic sensitive element;

FIG. 2 is an exploded perspective view of the holder;

FIG. 3 is a plan view showing the holder for magnetic sensitive elementsand a portion of a magnetic recording medium;

FIG. 4 is a cross-sectional side elevational view showing the essentialportion of a movable holder;

FIG. 5 is a perspective view showing one example of a magnetic encoderto which the holder for magnetic sensitive holders according to thepresent invention is applied;

FIG. 6 is a side elevational view showing one embodiment which ismounted on a circuit board whose circuit pattern is formed on thereverse side;

FIGS. 7 to 9 show modifications;

FIG. 7 is a perspective view showing a modification in which a fixedholder is modified;

FIG. 8 is a perspective view showing another modification in which leadframes are modified;

FIG. 9 is a perspective view showing yet another modification in whichlead frames are modified;

FIG. 10 is perspective view showing another embodiment in which a fixedholder is secured by a machine screw;

FIGS. 11A and 11B are perspective views showing holder structuresaccording to other embodiments;

FIG. 12 is a perspective view showing another example of a conventionalholder;

FIG. 13 is an exploded perspective view showing yet another conventionalholder;

FIG. 14 is an explanatory view showing the relationship between amagnetic recording medium and a magnetic sensitive surface when gapadjustment is effected by means of a conventional holder for magneticsensitive holders;

FIG. 15 is a graph showing the relationships between the gap, theeffective magnetic field strength and a magnetizing pitch;

FIG. 16 is a connection diagram of the resistors of the magneticsensitive element;

FIG. 17 is an output waveform diagram of the magnetic sensitive element;and

FIG. 18 is a plan view showing a conventional holder.

BEST MODE FOR CARRYING OUT THE INVENTION

The arrangement of the present invention will be explained in detailbelow with reference to the embodiments shown in the accompanyingdrawings.

A holder for magnetic sensitive elements according to the presentinvention comprises: a movable holder 3 for holding a magnetic sensitiveelement 4 to which flexible signal input/output member 5, . . . , 5 areconnected; a fixed holder 2 fixed to a board 1 for holding the movableholder 3; and a pair of guide means 2b, 3b for guiding the movableholder 3 for movement in one direction between the fixed holder 2 andthe movable holder 3, such that the movable holder 3 is moved in adirection perpendicular to a magnetic sensitive surface 4a of themagnetic sensitive element 4.

In the case of the illustrated embodiment, the fixed holder 2 is of amagnetic metal sheet made from a tin-plated iron sheet and bent formedinto a configuration having a dovetail groove therein as shown. Guideportions 2b are formed in a manner inclined inwardly from the upperportions of the respective side walls of the fixed holder 2, therebyyielding an elastic nature therein structurally. Those guide portions2b, therefore, serve to hold and guide the movable holder 3, allowingthe same to move therein in one direction only. In the illustratedembodiment, an elasticity is structurally given to the guide portions 2bby way of bending them, but an elastic material such as spring steel maybe employed. Projections 2a are formed on both sides of the fixed holder2, respectively, so that they can be fitted into mating positioningthrough-holes 1a formed in the board 1 or the like. In the illustratedembodiment, the projections 2a are formed by being cut part-way anderected from the bottom of the fixed holder 2 and thus integral with thefixed holder 2. However, this arrangement is not exclusive andseparately formed members analogous to the projections 2 may be fixedlikewise to the bottom of the fixed holder 2. The fixed holder 2 issecured to the circuit board 1 by inserting the projections 2a into therespective through-holes 1a formed in the board 1, positioning them at agiven point, and soldering a boundary A between the fixed holder 2 andthe board 1 or the boundary between the board 1 and the leading end ofeach projections 2a as shown in FIG. 6. It is noted that the aforesaidmovable holder's movement is effected in the fixed holder in a directionperpendicular to the magnetic sensitive surface 4a of the magneticsensitive element 4 fixed to the entire surface of the movable holder 3.The material of the fixed holder 2 is not limited to a specific kindbut, in terms of productivity, preferably, such a material should beused, which is solderable to the board 1, for example, an iron sheetplated with tin and other magnetic metallic sheets, magnetic powderedalloy, non-magnetic metal such as aluminum alloy, most preferably, asolderable magnetic metal plate which can assume an elastic structure.

The aforesaid movable holder 3 is bodily formed from a synthetic resinor the like, of an insulating nature, and guide portions 3b are formedintegrally with the movable holder 3, projecting from the opposite sidesthereof, respectively. The guide portions 3b engage with the respectiveguide portions 2b of the fixed holder 2 to constitute guide means. Arecess 3a is formed on the frontal surface of the movable holder 3, andthe magnetic sensitive element 4 is securely fitted in the recess 3a.The guide portions 3b include inclined surfaces which are slidinglymovable with respect to the corresponding guide portions 2b of the fixedholder 2. The sliding direction is perpendicular to the magneticsensitive surface 4a of the magnetic sensitive element 4. Adhesivereservoirs 3c are formed at locations above the respective guideportions 3b, whereby an adhesive agent is received in the reservoirs 3cso as to secure the movable holder 3c to the fixed holder 2. Also, abiasing magnet 7 is buried in the reverse side of the magnetic sensitiveelement 4 of the movable holder 3. The guide means, which is arrangedbetween the aforesaid fixed holder 2 and the movable holder 3, ispreferably of such material and configuration that can give the movableholder 3 an elastic pressing property or bias against the fixed holder 2perpendicular to the movement of the fixed holder and at a degreesufficient to temporarily secure the movable holder 3 at an arbitraryposition.

A plurality of flexible lead frames 5, . . . , 5 are secured to themovable holder 3 by means of an insert molding or the like, the framesbeing used as input/output members. In the illustrated embodiment, asshown in FIG. 4, the leading ends 5a of the respective lead frames 5 arebent upwardly and electrically connected to the front terminal portionof the magnetic sensitive element 4, while the other ends of the sameproject from the rear face of the movable holder 3 in a directionidentical to the above-mentioned direction in which the movable holder 3is moved. Those other ends of the lead frames 5 are so configured topermit their being secured to the circuit board 1. The portions of therespective lead frames 5, . . . , 5, which project from the movableholder 3, are formed into bent parts 5b and rear terminal parts 5c,wherein the latter 5c is soldered fast upon the circuit board 1. Thus,it is seen that, while the rear terminal portions 5c are secured to theboard 1, the movable holder 3 remains movable owing to the flexibilityof the lead frames 5 per se. The leading portions 5a of the respectivelead frames 5 are electrically connected to the terminal portion of themagnetic sensitive element 4 and protected with a sealant 6.

Several examples, each having the similar holder for magnetic sensitiveelements arranged in the above-described manner, and applied to amagnetic encoder, will now be explained below with reference to FIGS. 1to 3 and 5.

The holder for magnetic sensitive elements is secured at a predeterminedposition on the circuit board 1 by soldering or other fixing means.Positioning of the holder is accomplished by inserting the projections2a of the fixed holder 2 into the corresponding through-holes 1a of thecircuit board 1. The through-holes 1a are formed on the board 1 in aparallel relation with a tangent T of the magnetic recording medium 9.As shown in FIGS. 3 and 5, the magnetic drum 8 is rotatably disposed infront of the magnetic sensitive element 4 of the movable holder 3incorporated in the fixed holder 2. Also, the drum 8 is provided on itsouter periphery with the magnetic recording medium 9 having a series ofalternating magnetic poles N and S thereabout.

In the above-described embodiment, the fixed holder 2 and the terminalportions 5c of the lead frames 5 are secured to the circuit-pattern sideof the circuit board 1 by soldering. However, as shown in FIG. 6, thecircuit pattern is formed on the reverse side of the board 1, and theprojections 2a of the fixed holder 2 may be penetrated through the board1 to project at the reverse side thereof and secured thereto by dipsoldering or the like.

Now, hereinafter, a description will be made regarding the assembling ofthe magnetic sensitive element holder as well as the mounting of thesame upon a circuit board, which are all related above.

Firstly, the movable holder 3, which holds the magnetic sensitiveelement 4, inserted into between the guide portions 2b of the fixedholder 2, and then, the guide portions 3b of the movable holder 3 areclamped within the guide portions 2b by applying the elastic pressingforce of the latter to the former, so as to secure the movable holder 3in a provisionally unmoved state.

Next, the projections 2a of the fixed holder 2 are inserted into thecorresponding through-holes 1a of the circuit board 1 and located therein position. Then, soldering is effected, which preferably consists ofan automatic or dip soldering, using a reflow oven, in order to fix tothe circuit board 1 the boundaries A defined between the side faces ofthe fixed holder 2 and the board 1, and such is done also for fixing theterminal portions 5c of the lead frame 5 to the board 1. During suchprocess, preferably, to bend flat the projections 2a passing through thethrough-holes 1a, 1a, of the board 1, before soldering them, will ensurepreventing the fixed holder 2 against separation from the board, againstfall therefrom, and against dislocation.

Then an adjustment is made for varying the gap between the magneticsensitive element 4 and magnetic recording medium 9: The adjustmentinvolves rotating the magnetic drum 8, displacing the movable holder 3,during such rotation, while observing output values of the element 4,until the values reach an optimum one. In this respect, the fixed holder2 has been positioned unmoved in parallel with the tangent T of themagnetic recording medium 9, by means of which fixed holder 2, themovable holder 3 is retained for movement in a sole directionperpendicular to the tangent T of the magnetic recording medium 9. Thispermits movement of the magnetic sensitive surface 4a of the element 4to be executed in a parallel relation with the recording medium 9,simply by moving the movable holder 3, thus facilitating the gapadjustment. The movable holder 3 in the illustrated embodiment issecured to the circuit board 1 by soldering together the circuit board 1and the rear terminal portions 5c of the respective lead frames 5.However, the flexibility of bent portions 5b respectively of the leadframes 5, . . . , 5 enables the movable holder 3 to be moved freelytoward and away from the magnetic recording medium 9.

As may be required, the element holder 3, to which is fixed the signalinput/output member 5, may be retained on the fixed holder and subjectedto a soldering upon the circuit board 1.

When the gap adjustment has been completed, the movable holder 3 and thefixed holder 2, which are temporarily secured by the elastic pressuresapplied from the guide portions 2b and 3b, are completely fixed inposition by charging an adhesive between the corresponding guideportions 2b and 3b or by a mechanical fixing process such as caulking.In the case of fixation using the adhesive, the strength of adhesion canbe increased by charging the adhesive into the adhesive reservoirs 3c.

Although the aforesaid embodiment is a preferred embodiment of thepresent invention, various modifications can be employed withoutdeparting from the gist of the present invention. For example, as shownin FIG. 7, a platform-like projection 2c is formed at the bottom of thefixed holder 2, and the movable holder 3 may be mounted on theprojection 2c. In this arrangement, the area of contact between thefixed holder 2 and bottom face of the movable holder 3 reduced is incomparison with the other embodiments described above, which thereforecreates a less frictional, easy movement of the movable holder 3 duringthe gap adjustment. Additionally, it advantageously impedes heatconductivity in the soldering process for fixation of the fixed holderto the board 1.

As needed, the lead frames 5, . . . , 5 may be so formed that itprojects from the upper part of the reverse face of the movable holder3, as shown in FIG. 8, or from one lateral wall of the movable holder 3,as in FIG. 9. In the holder structure shown in FIG. 9, it is essentiallydesired that the signal input/output element be made of a materialhaving a non-directional flexibility, such as a lead wire, instead ofthe lead frames 5, . . . , 5 having unidirectional flexibility.

Referring to FIG. 10, the fixed holder 2 may be provided with apositioning pin 2d and a screw-mounting hole 2e. The fixed holder 2 maybe fixed in position by means of the pin 2d being securely inserted in apositioning hole (not shown) formed in the circuit board 1, as well asby means of the machine screw 10 being drived into the board 1 throughthe screw-mounting hole 2e. The fixation of the holder 2, in thisembodiment, being made by the screw 10 and pin 2d, permits use of anunsolderable material for forming the holder 2, for instance, a plasticmaterial. The fixed holder 2 is, on the top ends of its respectivelateral walls, formed with inwardly inclined guide portions 2d, tothereby define dovetail space or groove in which is accommodated themovable holder 2. It is noted that the fixed and movable holders 2, 3may be made of the same material, for example, a resin material, inwhich case, they may have a same coefficient for thermal expansion, andthus, temperature does not affect the positioning of the holder,offering an improvement to the holder positioning or locating accuracy.

As another mode for engaging together the movable and fixed holders 3,2, a dovetail engagement means may be provided on both bottom surfacesof the movable and fixed holders 3, 2, in order to permit guiding andmoving the movable holder 3 in one direction along the fixed holder 2.Reference is made to FIG. 11A, for instance, from which it can be seenthat a magnetic metallic plate, forming the fixed holder 2, is formedsuch as to define two guide portions 2b which constitutes a maledovetail engagement part as illustrated, or otherwise a female one,whereas the bottom face of the movable holder 3 is formed with a matingfemale dovetail engagement part, or otherwise a male one, to define twoguide portions 3b, whereupon, as indicated, engaging together thoseguide portions 2b, 3b results in retaining the movable holder 3 formovement in a direction perpendicular to the magnetic sensitive surface4a. In this arrangement, the fixing of the movable holder 3 to the fixedholder 2 is accomplished by charging an adhesive between the side facesof the fixed holder 2 and the side faces of the movable holder 3 andinto the adhesive reservoirs 3c. As shown in FIG. 11B, the fixed holder2 may be a thin sheet fixed holder which is formed from the guideportions 2b made from male or female dovetails by machining such ascutting or extrusion. In this arrangement, since the fixed holder 2 ismade of elastic material or since the guide portions 3b of the movableholder 3 have elasticity, predetermined elastic pressures can beproduced between the guide portions 2b and 3b. In the holder structureshown in FIGS. 11A and 11B, it suffices to form the positioningprojections 2a with the fixed holder 2 equal in width to the movableholder 3. Accordingly, it is possible to make the entire holder compact.

We claim:
 1. A holder for a magnetic sensitive element having a magneticsensitive surface, said magnetic sensitive element being disposed inopposed relation to magnetic recording medium, with a gap providedtherebetween, said holder comprising:a movable holder which is connectedto a flexible signal input/output member, said movable holder holdingsaid magnetic sensitive element; a fixed holder which is fixed to aboard and formed from an elastic material, said fixed holder holdingsaid movable holder in such a manner as to allow said movable holder tomove in a direction perpendicular to said magnetic sensitive surface ofsaid magnetic sensitive element, while simultaneously applying a firstbiasing force to said movable holder in a direction perpendicular to theline of movement of said movable holder for lateral movement relative tosaid fixed holder, simultaneous with a second biasing force appliedperpendicular to said lateral movement of said movable holder by saidfixed holder, and a guide means positioned between said movable andfixed holders, said movable holder thereby moving in a directionperpendicular to the magnetic sensitive surface of said magneticsensitive element, said perpendicular direction to said magneticsensitive surface, to permit adjustment of said gap between saidmagnetic sensitive element and said magnetic recording medium; whereinsaid first and second biasing forces of said fixed holder act tonormally retain said movable holder thereon, while permitting the sameto be movable thereon, so that said movable holder may be moved andretained at a desired point for said gap adjustment on said movableholder in such a manner as to permit movement of said movable holder ofsaid gap adjustment, so that said movable holder may be both movable andtemporarily securable at a desired point.
 2. The holder for magneticsensitive elements according to claim 1, wherein a pair of right andleft guide portions having inwardly inclined surfaces are formed on saidfixed holder, while a pair of right and left guide portions havinginclined surfaces which slide on said respective guide portions of saidfixed holder are formed to project from said movable holder, and whereinsaid guide means is formed by fitting said guide portions of saidmovable holder between the guide portions of said fixed holder.
 3. Theholder for magnetic sensitive elements according to claim 1, whereinsaid fixed holder is formed of an elastic material, and wherein saidguide portions of said movable holder are held by the elastic pressuresapplied by said guide portions of said fixed holder.
 4. The holderaccording to claim 1, wherein said signal input/output member is so bentas to yield a flexibility for enabling movement of said movable holder,to thereby permit adjustment of a gap present between said magneticsensitive surface and said magnetic recording medium.
 5. The holderaccording to claim 1 wherein said guide means is formed by a guideportion of said fixed holder and a mating guide portion of said movableholder corresponding to said fixed holder guide portion, wherein bothsaid guide portions of said fixed and movable holders are slidablyengaged such that said movable holder may be moved back and forth forsaid gap adjustment, and wherein said biasing force is applied to saidguide portion of said movable holder.
 6. The holder according to claim5, wherein an adhesive reservoir is formed in an upper portion of saidguide portion associated with said movable holder.
 7. The holderaccording to claim 1, wherein an adhesive reservoir means is formed insaid guide means.
 8. The holder according to claim 1, wherein said fixedholder is fixed to said board by soldering.
 9. The holder according toclaim 1, wherein said fixed holder is formed from a material selectedfrom the group consisting of synthetic resin and a magnetic metallicsheet.
 10. The holder according to claim 1, wherein both said movableand fixed holders are formed generally in a dovetail shape at theirrespective portions corresponding to said guide means.
 11. The holderaccording to claim 1, wherein one of said movable and fixed holders isformed with a male dovetail engagement portion, whereas another of saidmovable and fixed holders is formed with a female dovetail portion;wherein said male and female dovetail portions constitute said guidemeans, and wherein both said movable and fixed holders are slidablyengaged together at said male and female dovetail portions, such thatone of said male and female dovetail portions produces said biasingforce.
 12. The holder according to claim 1, wherein said fixed holder isprovided with a means for reducing the area of contact of said fixedholder with said movable holder.
 13. The holder according to claim 12,wherein said reducing means comprises a platform-like projected portionformed at a bottom wall of said fixed holder.
 14. The holder accordingto claim 11, wherein said fixed holder is provided with a positioningpin and a screw-mounting hole, and wherein said fixed holder is fixed inposition upon said board by a machine screw driven into said boardthrough said screw-mounting hole as well as by said positioning pin.